Electrical connectors continue to be used in harsh environments in which the connectors are subjected to vibration and the like, i.e. the passenger compartment of a car. In these environments it is important to design the connectors in such a manner so as to ensure that a positive electrical connection will be effected and maintained. In particular, it is important to provide a sufficient secondary locking element in order to prevent the terminals from unwanted removal from the housing.
One type of latching member is shown in Japanese UM Publication Number 58470/88. The latching member has flexible latching arms which are inserted in the housing. The latching member is designed to move with respect to the housing between a primary position and a secondary position. In the primary position, terminals may be inserted into respective terminal-receiving cavities. In the secondary position, latching-projection sections of latching arms are moved into engagement with the inner ends of the electrical contact sections at intermediate positions of the terminals to prevent each terminal from slipping out in the direction opposite to the insertion of such terminals.
However, a connector of the type described requires a relatively strong pushing force to insert the latching arms into the housing to move the latching-projections sections of the latching arms into engagement with the terminals. This force is necessitated because the portions adjacent to the latching projections are forced to be deformed downwardly by sloped surfaces of the upper walls of the terminal-receiving cavities. Such forceful insertion is not easy and may cause fatigue and permanent deformation of the latching arms. Moreover, since means for maintaining the primary and secondary latching positions are formed at the sides of the latching member and the housing, the secondary latching of the latching member to the housing becomes insufficient at a central part of the connector, particularly if the connector is an elongated multi-terminal type, thereby causing the latching arms in the central portions to operate improperly.
U.S. Pat. No. 5,004,436, in an effort to avoid some of the problems described above, discloses latching arms of the latching member which latch the respective terminals in the terminal-receiving cavities without forcing the latching arms to deform in the terminal-receiving cavities. Also, the primary and secondary latching is performed at the center of the housing, as well as the sides, thereby providing a more reliable connection.
Several problems still exist with the type of connector disclosed in U.S. Pat. No. 5,004,436. Although the primary and secondary latching positions are spaced apart, it is conceivable that respective latching arms of an elongated connector will not properly be held in the primary or preinsertion position, particularly if the connector is bowed. Also, the latching arms of the prior art connectors are moved into the terminal-receiving cavities as the latch member is moved from the primary latching position to the secondary latching position. This type of movement does not provide for the terminal position assurance function required by the industry.